The invention is related to a load-sensitive twin brake power controller.
A twin brake power controller of the kind under review is known from the German patent specification No. 3,315,763. For the actuation of the control pistons, this controller is furnished with a rocking element which has an axially symmetrical configuration. The loaded ends of the control pistons, the rocking element and part of a control tappet which is fixed to the load-sensitive movable lever are disposed within a cylindrical chamber which is mill cut into the housing. A dust cover seat is milled around said chamber into the housing edge around which a rolling diaphragm-type dust cover is clamped which defines said cylindrical chamber at the front face. The control tappet leads into this chamber from the outside through a central hole in the dust cover. The dust cover fastens behind a circumferential bead at the control tappet.
The use of rocking elements, irrespective of what their shape may be, has proved useful in the load-sensitive actuation of twin controllers. A flexible dust cover fixed to the housing is indispensable in order that the control piston ends projecting into the chamber, which is free of hydraulic pressure fluid, and their seals are protected against soiling. The housing is cut at low cost from a strand which is extruded with the profile section of the housing. The cylindrical chamber, however, has to be fabricated subsequently by a machining operation just like the seat of the dust cover. As a consequence, substantial material is wasted and a substantial amount of labor is required.